JP3266722B2 - Ultrasonic motor drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic motor driving device for driving a driving body which is in contact with a piezoelectric vibrator.

[0002]

2. Description of the Related Art As shown in FIG. 3, the present applicant divides electrodes 2, 3 provided on both ends of a piezoelectric vibrator 1 into, for example, two, and divides the divided electrodes 2a, 2b, 3a. ,
The dividing lines 2c and 3c of 3b are provided so as to be orthogonal to each other, the electrodes 2a and 2b are connected to the oscillator 5 via the switch 4, the electrode 3b is grounded, and the end face of the piezoelectric vibrator 1 or An ultrasonic motor with a driving body in contact with the side was proposed.

In this ultrasonic motor, a switch 4 is connected to a terminal a.
, The output of the oscillator 5 is applied to the electrode 2 of the piezoelectric vibrator 1.
a, and flows to the ground through the electrode 3b and returns to the oscillator 5 from the ground, so that a voltage is applied to the piezoelectric vibrator 1 in a direction perpendicular to the piezoelectric vibrator 1 and a traveling wave is generated in the direction of the arrow. Is brought into contact with the end face or side face of the piezoelectric vibrator 1 to drive the driving body.

[0004]

However, in this ultrasonic motor driving device, since the driving portion of the piezoelectric vibrator 1 is half, the efficiency is low and a high voltage must be applied. There was a problem.

[0005]

According to the present invention, the output of an oscillator is divided by a phase determination circuit into four signals having phases different from each other by 90.degree., And the signals having different phases are switched between a voltage V0 and a ground voltage. A switch is input to a switching circuit connected thereto, an output of the switching circuit is input to a driving circuit, and four outputs of the driving circuit are connected to four electrodes provided equally on one surface of the piezoelectric vibrator, The four electrodes, which are similarly provided on the other surface of the piezoelectric vibrator, are connected by being shifted one by one and input, and two of the four outputs of the drive circuit are added by a doubler 14. Then, the added output of the doubling circuit is amplified by an amplifier and positively fed back to the oscillator, whereby the entire circuit operates as an oscillation circuit, and a stable traveling wave is generated in the piezoelectric vibrator. Press against the vibrator Is intended to drive the driving member,
The changeover switch connected to the changeover circuit changes the direction of the traveling wave generated in the piezoelectric vibrator by being connected to either the voltage V0 or the ground voltage.

[0006]

According to the present invention, the output of the oscillator is divided into four signals whose phases are shifted by 90 degrees by the phase determining circuit, and these four outputs are input to the switching circuit, whereby the output of the switch connected to the switching circuit is reduced. The phase is switched by the voltage of.

In the phase determining circuit, 4
The outputs of the two signals are input to the drive circuit, and the signals amplified by the drive circuit are input to the four electrodes on one surface of the piezoelectric vibrator and shifted by one to the four electrodes on the other surface. By being connected to the electrodes, a traveling wave is generated in the piezoelectric vibrator, and a driving body pressed against the piezoelectric vibrator can be driven, and two signals input to the piezoelectric vibrator are added. By amplifying with an amplifier and positively feeding back to the oscillator, the whole circuit can operate stably.

[0008]

FIG. 1 is a block diagram of an ultrasonic motor driving apparatus according to an embodiment of the present invention. When an oscillator 6 outputs a clock pulse having a constant period as shown in FIG. Outputs four signals having different phases by 90 degrees as shown in (b), (c), (d), and (e) of FIG.

A changeover switch 9 is connected to the changeover circuit 8, and the changeover switch 9 is switched between a predetermined voltage V0 and a ground voltage, is always connected to the ground voltage, and is switched to the voltage V0 when inverted. Can be

The output of the switching circuit 8 is supplied to the driving circuit 10
To the piezoelectric vibrator 11
Are input to the electrodes.

The electrode 12 on one surface of the piezoelectric vibrator 11
a, 12b, 12c, and 12d are electrodes 13a on the other surface,
13b, 13c, and 13d.
Is input to the electrodes 12a and 13b, the second output is input to the electrodes 12b and 13c, the third output is input to the electrodes 12c and 13d, and the fourth output is the electrode 12d. The output from the drive circuit 10 is input to the electrode 13a and to the electrode on one surface of the piezoelectric vibrator 11 and the electrode on the other surface which is shifted by one.

Then, the two outputs of the driving circuit 10 are added by the doubling circuit 14 to become a signal shown in FIG.
This signal is amplified by the amplifier 15 and is positively fed back to the oscillator 6, whereby the entire circuit operates as an oscillation circuit, and supplies a stable output to the piezoelectric vibrator 11, thereby being pressed against the piezoelectric vibrator 11. The driving body is driven smoothly.

[0013]

As described above, in the ultrasonic motor driving apparatus according to the present invention, the output of the oscillator is divided by two and divided into four, and the divided output is input to the four divided electrodes of the piezoelectric vibrator. By doubling the divided output and feeding it back to the oscillator,
The whole circuit operates as an oscillator, and a stable output can be input to the piezoelectric vibrator, and accurate control can be performed with a rough oscillator.

[Brief description of the drawings]

FIG. 1 is a block diagram of an ultrasonic motor driving device according to an embodiment of the present invention.

FIG. 2 is an output waveform diagram of each unit in the block diagram of FIG.

FIG. 3 is a block diagram of an ultrasonic motor driving device proposed by the present applicant.

[Explanation of symbols]

 Reference Signs List 6 oscillator 7 phase determination circuit 8 switching circuit 9 switching switch 10 waveform shaping circuit 11 drive circuit 12 piezoelectric vibrator 15 doubler circuit 16 amplifier

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H02N 2/00

Claims (2)

(57) [Claims] An output of an oscillator is divided into four signals having different phases by 90 ° by a phase determination circuit, and a switching circuit is connected to a switching switch for switching the four signals having different phases to a voltage V0 and a ground voltage. The output of the switching circuit is input to a drive circuit, and the four outputs of the drive circuit are connected to four equally provided electrodes on one surface of the piezoelectric vibrator, and the other surface of the piezoelectric vibrator is connected. The four outputs provided in the same manner are connected one by one while being shifted and input, and two of the four outputs of the driving circuit are added by a doubling circuit 14, and the added doubling is performed. By amplifying the output of the circuit with an amplifier and positively feeding back to the oscillator, the entire circuit operates as an oscillation circuit, generates a stable traveling wave on the piezoelectric vibrator, and drives the driving body pressed against the piezoelectric vibrator. Specially to drive Ultrasonic motor drive device. 2. A switching switch connected to the switching circuit changes a direction of a traveling wave generated in the piezoelectric vibrator by being connected to one of the voltage V0 and a ground voltage. The ultrasonic motor drive device according to claim 1.